Apparatus and Method for Manufacturing Electrode Assembly

ABSTRACT

A method for manufacturing an electrode assembly comprises: a primary stack manufacturing step in which a first electrode and a second electrode are alternately stacked with a separator on a top surface of a table; a secondary stack manufacturing step in which the first electrode and the second electrode are alternately stacked with the separator on the primary stack so that the second electrode is stacked to be disposed at the lowermost end; a stack rotating step in which the primary stack and the secondary stack are rotated together at an angle of 180° to change positions of the primary stack and the secondary stack; and an electrode assembly manufacturing step in which the first electrode and the second electrode are alternately stacked with the separator on the primary stack so that the second electrode is stacked to be disposed at the lowermost end to manufacture a tertiary stack.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of the priority of KoreanPatent Application No. 10-2019-0148933, filed on Nov. 19, 2019, which ishereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to an apparatus and method formanufacturing an electrode assembly, which are capable of manufacturinga symmetrical electrode assembly in a new stacking manner.

BACKGROUND ART

In general, secondary batteries refer to chargeable and dischargeablebatteries, unlike primary batteries that are not chargeable. Thesecondary batteries are being widely used in the high-tech electronicfields such as mobile phones, notebook computers, and camcorders.

The secondary batteries are classified into a can-type secondarybattery, in which an electrode assembly is embedded in a metal can, anda pouch-type secondary battery in which an electrode assembly isembedded in a pouch.

The can-type secondary battery comprises an electrode assembly, anelectrolyte, a can for accommodating the electrode assembly and theelectrolyte, and a cap assembly mounted on an opening of the can, andthe pouch-type secondary battery comprises an electrode assembly, anelectrolyte, and a pouch accommodating the electrode assembly and theelectrolyte.

The electrode assembly is classified into a stacked structure, a woundtype (jelly-roll type) structure, or a stack/folding type structure. Thestacked structure has a structure in which electrode units (a positiveelectrode, a separator, and a negative electrode) constituting theelectrode assembly are stacked separately from each other.

However, it is very difficult to precisely align the electrode assemblyin the stacked electrode assembly described above, and in particular,there is a problem in that a defect occurs while the electrode assemblyis bent.

DISCLOSURE OF THE INVENTION Technical Problem

The present invention is invented to solve the above problems, and anobject of the present invention is to provide an apparatus and methodfor manufacturing an electrode assembly, in which a new stacking methodfor the electrode assembly is proposed to improve alignment of theelectrode assembly and prevent the electrode assembly from being bent,and in particular, an electrode assembly of which upper and lowerportions are symmetrical to each other is manufactured.

Technical Solution

A method for manufacturing an electrode assembly according to thepresent invention for achieving the above object comprises: a primarystack manufacturing step (S10) in which a first electrode and a secondelectrode are alternately stacked with a separator therebetween on a topsurface of a table so that the first electrode is stacked to be disposedat each of the uppermost end and the lowermost end; a secondary stackmanufacturing step (S20) in which the first electrode and the secondelectrode are alternately stacked with the separator therebetween on theprimary stack so that the second electrode is stacked to be disposed atthe lowermost end; a stack rotating step (S30) in which the primarystack and the secondary stack, which are disposed on the table, arerotated together at an angle of 180° to change positions of the primarystack and the secondary stack; and an electrode assembly manufacturingstep (S40) in which the first electrode and the second electrode arealternately stacked with the separator therebetween on the primary stackso that the second electrode is stacked to be disposed at the lowermostend to manufacture a tertiary stack.

The stack rotating step (S30) may comprise a process (S31) of gripingthe primary stack and the secondary stack, which are disposed on thetable, together by using a gripper, a process (S32) of allowing thetable to descend away from the primary stack, a process (S33) ofrotating the primary stack and the secondary stack together at an angleof 180° through the gripper, and a process (S34) of allowing the tableto ascend to be supported on the secondary stack.

The stack rotating step (S30) may further comprise a process (S31 a) ofphotographing the lowermost end of the primary stack disposed on thetable by using a first photographing part and measuring a primaryreference line of the primary stack from a photographed image betweenthe process (S31) and the process (S32), a process (S35) ofphotographing the uppermost end of the primary stack by using a secondphotographing part and measuring a secondary reference line of theprimary stack from a photographed image after the process (S34), and aprocess (S36) of comparing positions of the primary reference line andthe secondary reference line with each other through a measuring part tocalculate an error value.

The reference line may be a line by which the primary stack disposed onthe table is equally divided to be symmetrical to each other in a widthdirection or a longitudinal direction.

In the electrode assembly manufacturing step (S40), the separator, thefirst electrode, and the second electrode may move by the error valueand be stacked on the primary stack.

The electrode assembly manufactured by the electrode assemblymanufacturing step (S40) may have a stacked structure of which upper andlower portions are symmetrical to each other with respect to a center.

The primary stack manufacturing step (S10) may comprise a process ofallowing the table to descend so that the uppermost end of the stackstacked on the table is constantly maintained in height.

The electrode assembly manufacturing step (S40) may comprise a processof allowing the table to descend so that the uppermost end of the stackstacked on the table is constantly maintained in height.

In secondary stack manufacturing step (S20), the second electrode may bestacked at the uppermost end.

In the electrode assembly manufacturing step (S40), the second electrodemay be stacked at the uppermost end.

The method may further comprise, after the electrode assemblymanufacturing step (S40), a bonding step (S50) of pressing the electrodeassembly at a set pressure to bond the electrode assembly.

An apparatus for manufacturing an electrode assembly according to thepresent invention comprises: a table; a loading member configured toalternately stack a first electrode and a second electrode with aseparator therebetween on a top surface of the table to manufacture astack; a gripper configured to grip the stack stacked on the table torotate the stack at an angle of 180°; and a measuring member comprisinga first photographing part configured to primarily photograph thelowermost end of the stack stacked on the table, a second photographingpart configured to secondarily photograph the uppermost end of the stackafter rotating the stack at the angle of 180°, and a measuring partconfigured to calculate an error value by comparing a primary referenceline measured from a primarily photographed image of the stack with asecondary reference line measured from a secondarily photographed imageof the stack.

The loading member may be configured to stack the separator, the firstelectrode, and the second electrode on the top surface of the stackwhile moving by the error value after rotating the stack at the angle of180°.

When the gripper grips the stack, the table may descend away from thestack.

Each of the photographing parts may comprise an infrared camera.

Advantageous Effects

The method for manufacturing the secondary battery according to thepresent invention may comprise the primary stack manufacturing step(S10), the secondary stack manufacturing step (S20), the stack rotatingstep (S30), and the electrode assembly manufacturing step (S40).Therefore, the electrode assembly may be manufactured through the newstacking method, and the electrode assembly of which the upper and lowerportions are symmetrical to each other, may be manufactured.Particularly, the electrode assembly may be prevented from being bent.

In addition, in the method for manufacturing the secondary batteryaccording to the present invention, the stack rotating step (S30) maycomprise the process (S31) of griping the primary and secondary stacksby using the gripper, the process (S32) of allowing the table to descendaway from the primary stack, the process (S33) of rotating the primaryand secondary stacks at the angle of 180° through the gripper, and theprocess (S34) of allowing the table to ascend so as to be supported onthe secondary stack. Therefore, the secondary stack may be stablyrotated.

In addition, in the method for manufacturing the secondary batteryaccording to the present invention, the stack rotating step (S30)comprises the process of comparing the reference line of the primarystack before the rotation with the reference line of the primary stackafter the rotation between the step (S31) and the step (S32). Therefore,it may be possible to check the position change of the primary stack,and thus, the stacked position may be corrected through the error valuedue to the changed position, thereby preventing the stacking failurefrom occurring.

In addition, in the method for manufacturing the secondary batteryaccording to the present invention, the reference line may be set as theline by which the primary stack is equally divided to be symmetrical toeach other in the width direction or the longitudinal direction.Therefore, the reference line of the radial unit may be set identically.

In addition, in the method for manufacturing the secondary batteryaccording to the present invention, the electrode assembly manufacturingstep (S40) may be performed so that the separator, the first electrode,and the second electrode move by the error value and then are stacked onthe secondary stack. Therefore, the stacking failure may be previouslyprevented.

In the method for manufacturing the secondary battery, the primary stackmanufacturing step (S10) may be performed so that the table on which theelectrode and the separator are stacked constantly descends. Therefore,the height of the uppermost end of the stack stacked on the table may beconstantly maintained to improve the stacking efficiency.

In the method for manufacturing the secondary battery, the electrodeassembly manufacturing step (S240) may be performed so that the table onwhich the secondary stack is disposed constantly descends. Therefore,the height of the uppermost end of the stack stacked on the table may beconstantly maintained to improve the stacking efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an electrode assembly according to afirst embodiment of the present invention.

FIG. 2 is a flowchart illustrating a method for manufacturing anelectrode assembly according to a second embodiment of the presentinvention.

FIG. 3 is a cross-sectional view illustrating a primary stackmanufacturing step (S10) in the method for manufacturing the electrodeassembly according to the second embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a secondary stackmanufacturing step (S20) in the method for manufacturing the electrodeassembly according to the second embodiment of the present invention.

FIGS. 5 to 8 are cross-sectional views illustrating a stack rotatingstep (S30) in the method for manufacturing the electrode assemblyaccording to the second embodiment of the present invention.

FIG. 9 is a cross-sectional view illustrating an electrode assemblymanufacturing step (S40) in the method for manufacturing the electrodeassembly according to the second embodiment of the present invention.

FIG. 10 is a cross-sectional view illustrating a bonding step (S50) inthe method for manufacturing the electrode assembly according to thesecond embodiment of the present invention.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings in such a manner thatthe technical idea of the present invention may easily be carried out bya person with ordinary skill in the art to which the invention pertains.The present invention may, however, be embodied in different forms andshould not be construed as limited to the embodiments set forth herein.In the drawings, anything unnecessary for describing the presentinvention will be omitted for clarity, and also like reference numeralsin the drawings denote like elements.

[Electrode Assembly According to First Embodiment of the PresentInvention]

As illustrated in FIG. 1, an electrode assembly 10 according to a firstembodiment of the present invention comprises a primary stack 10 a, asecondary stack 10 b disposed under the primary stack 10 a, and atertiary stack 10 c disposed on the primary stack 10 a.

Primary Stack

In the primary stack 10 a, a first electrode 11 and a second electrode12 are alternately stacked with the separator 13 therebetween. Here, thefirst electrode 11 is disposed at each of the uppermost and lowermostends. That is, in the primary stack 10 a, an upper portion and a lowerportion have the same stacked structure with respect to the secondelectrode 12, which is disposed between the upper and lower portions.

For example, the primary stack 10 a has a five-layered structure inwhich the first electrode 11, the separator 13, the second electrode 12,the separator 13, and the first electrode 11 are sequentially stacked.

Secondary Stack

In the secondary stack 10 b, when viewed in FIG. 1, the secondary stack10 b is disposed under the primary stack 10 a, and the first electrode11 and the second electrode are alternately stacked with the separator13 therebetween. Here, the second electrode 12 is stacked to be disposedat the uppermost end corresponding to the primary stack 10 a.Alternatively, the separator 13 is interposed between the firstelectrode 11 disposed at the lowermost end of the primary stack 10 a andthe second electrode 12 disposed at the uppermost end of the secondarystack 10 b.

For example, the secondary stack 10 b has a ten-layered structure inwhich the separator 13, the second electrode 12, the separator 13, thefirst electrode 11, the separator 13, the second electrode 12, theseparator 13, the first electrode 11, the separator 13, and the secondelectrode 12 are sequentially stacked in a vertical direction. Here, thesecond electrode 12 is also disposed at the lowermost end of thesecondary stack 10 b.

Tertiary Stack

When viewed in FIG. 1, the tertiary stack 10 c is disposed on theprimary stack 10 a and has a stacked structure that is symmetrical tothe secondary stack 10 b with respect to the primary stack 10 a.

In the tertiary stack 10 c, the first electrode 11 and the secondelectrode 12 are alternately stacked with the separator 13 therebetweenon the primary stack 10 a. Here, the second electrode 12 is disposed atthe lowermost end corresponding to the primary stack 10 a.Alternatively, the separator 13 is interposed between the firstelectrode 11 disposed at the uppermost end of the primary stack 10 a andthe second electrode 12 disposed at the lowermost end of the secondarystack 10 b.

For example, the tertiary stack 10 c has a ten-layered structure inwhich the second electrode 12, the separator 13, the first electrode 11,the separator 13, the second electrode 12, the separator 13, the firstelectrode 11, the separator 13, the second electrode 12, and theseparator 13 are sequentially stacked in the vertical direction. Here,the second electrode 12 is also disposed at the uppermost end of thetertiary 10 c.

The first electrode is a positive electrode, and the second electrode isa negative electrode, and vice versa.

Therefore, in the electrode assembly 10 according to the firstembodiment of the present invention, the tertiary stack 10 c, theprimary stack 10 a, and the secondary stack 10 b are stacked in thevertical direction, but the secondary stack 10 b and the tertiary stack10 c have a symmetrically stacked structure with respect to the primarystack 10 a.

The electrode assembly 10 having the above-described structure accordingto the first embodiment of the present invention is manufactured usingan apparatus 100 for manufacturing the electrode assembly.

[Apparatus for Manufacturing Electrode Assembly According to SecondEmbodiment of the Present Invention]

Referring to FIGS. 1, 5, and 10, an apparatus 100 for manufacturing anelectrode assembly according to a second embodiment of the presentinvention comprises a table 110, a loading member 120 configured toalternately stack a first electrode and a second electrode with aseparator therebetween on a top surface of the table 110, a gripper 130configured to grip the stack stacked on the table 110 to rotate thestack at an angle of 180°, a measuring member 140 comprising a firstphotographing part 141 configured to primarily photograph the lowermostend of the stack stacked on the table 110, a second photographing part142 configured to secondarily photograph the uppermost end of the stackafter rotating the stack at the angle of 180°, and a measuring part 143configured to calculate an error value by comparing a primary referenceline measured from a primarily photographed image of the stack with asecondary reference line measured from a secondarily photographed imageof the stack, and a bonding member 150 configured to bond the stack.

The loading member 120 is configured to stack the separator, the firstelectrode, and the second electrode on the top surface of the stackwhile moving by the error value after rotating the stack at the angle of180°, thereby preventing stacking failure from occurring.

When the gripper 130 grips the stack, the table 110 may descend awayfrom the stack to prevent the stack from being caught on the table 110when the stack is rotated.

Each of the first and second photographing parts 141 and 142 may be aninfrared camera and thus accurately photograph the stack disposed on thetable 110 to measure a reference line of the stack.

Hereinafter, a method for manufacturing the electrode assembly by usingthe apparatus 100 for manufacturing the electrode assembly, which hasthe above-described constituents, according to the second embodiment ofthe present invention will be described.

[Method for Manufacturing Electrode Assembly According to SecondEmbodiment of the Present Invention]

As illustrated in FIGS. 2 to 10, a method for manufacturing an electrodeassembly according to a second embodiment of the present inventioncomprises a primary stack manufacturing step (S10), a secondary stackmanufacturing step (S20), a stack rotating step (S30), an electrodeassembly manufacturing step (S40) in which a tertiary stack ismanufactured to complete an electrode assembly, and a bonding step (S50)of bonding the primary stack, the secondary stack, and the tertiarystack to each other.

Primary Stack Manufacturing Step

As illustrated in FIG. 3, in the primary stack manufacturing step (S10),a first electrode 11 and a second electrode 12 are alternately stackedwith a separator 13 therebetween on a top surface of a table 110 tomanufacture a primary stack 10 a. Here, the first electrode 11 isstacked to be disposed at each of the uppermost and lowermost ends ofthe primary stack 10 a. The table 110 has a flat top surface so that theprimary stack 10 a is disposed horizontally.

For example, in the primary stack manufacturing step (S10), a loadingbox in which the first electrode 11 is loaded, a loading box in whichthe second electrode 12 is loaded, and a loading box in which theseparator 13 is loaded are prepared. Then, the first electrode 11, thesecond electrode 12, and the separator 13, which are loaded in theloading boxes, are selectively drawn out by using a loading member 120so as to be stacked on the top surface of the table 110. That is, thefirst electrode 11, the separator 13, the second electrode 12, theseparator 13, and the first electrode 11 are sequentially stacked on thetop surface of the table 110 using the loading member 120 to manufacturea primary stack 10 a having a five-layered structure.

The primary stack manufacturing step (S10) further comprises a processof pressing the primary stack 10 a at a set pressure to bond the primarystack 10 a. Thus, the first electrode 11, the second electrode 12, andthe separator 13, which are disposed in the primary stack 10 a, may beprevented from moving.

The primary stack manufacturing step (S10) further comprises a processof allowing the table 110 to descend so that the uppermost end of thestack stacked on the table 10 is constantly maintained in height.Therefore, it is not necessary to adjust the height of the loadingmember 120, and thus, the electrodes and the separators may be stablystacked on the table 110.

Secondary Stack Manufacturing Step

As illustrated in FIG. 4, in the secondary stack manufacturing step(S20), a secondary stack 10 b is manufactured on a top surface of theprimary stack 10 a disposed on the table 110.

That is, in the secondary stack manufacturing step (S20), the firstelectrode 11 and the second electrode 12 are alternately stacked withthe separator 13 therebetween on the primary stack 10 a to manufacturethe secondary stack 10 b. Here, the second electrode 12 is stacked to bedisposed at the lowermost end of the secondary stack 10 b.

For example, in the secondary stack manufacturing step (S20), asecondary stack 10 b having a ten-layered structure in which the secondelectrode 12, the separator 13, the first electrode 11, the separator13, the second electrode 12, the separator 13, the first electrode 11,the separator 13, the second electrode 12, and the separator 13 aresequentially stacked on the top surface of the primary stack 10 adisposed on the table 110 in the vertical direction is manufactured.Here, upper and lower portions of the secondary stack have asymmetrically stacked structure with respect to a center of thesecondary stack.

Thus, the primary stack 10 a and the secondary stack 10 b are disposedon the top surface of the table 110.

The secondary stack manufacturing step (S20) further comprises a processof bonding the first stack 10 a and the secondary stack 10 b. That is,the primary stack 10 a and the secondary stack 10 b, which are disposedon the table 110, may be pressed at the set pressure to improve bondingforce between the primary stack 10 a and the secondary stack 10 b.

Stack Rotating Step

As illustrated in FIGS. 5 to 8, in the stack rotating step (S30), theprimary stack 10 a and the secondary stack 10 b are rotated so that theprimary stack 10 a is disposed on the secondary stack 10 b.

That is, the stack rotating step (S30) comprises a process (S31) ofgriping the primary stack 10 a and the secondary stack 10 b, which aredisposed on the table 110, together by using a gripper 130, a process(S32) of allowing the table 110 to descend away from the secondary stack10 b so that the table 110 is not caught when the primary stack 10 a andthe secondary stack 10 b are rotated, a process (S33) of rotating theprimary stack 10 a and the secondary stack 10 b together at an angle of180° through the gripper 130, and a process (S34) of allowing the table110 to ascend to be supported on the secondary stack 10 b.

That is, the primary stack 10 a is disposed at an upper side, and thesecondary stack 10 b is disposed at a lower side.

The stack rotating step (S30) comprises a process of measuring aposition error before and after the rotation of the primary stack 10 aand the secondary stack 10 b by using a measuring member 140. Themeasuring member 140 comprises a first photographing part 141, a secondphotographing part 142 and a measuring part 143.

That is, the stack rotating step (S30) comprises a process (S31 a) ofphotographing the lowermost end of the primary stack 10 a disposed onthe table by using the first photographing part 141 and measuring aprimary reference line O1 of the primary stack 10 a from a photographedimage between the process (S31) and the process (S32), a process (S35)of photographing the uppermost end of the primary stack 10 a by usingthe second photographing part 142 and measuring a secondary referenceline O2 of the primary stack 10 a from a photographed image after theprocess (S34), and a process (S36) of comparing positions of the primaryreference line O1 and the secondary reference line O2 with each otherthrough the measuring part 143 to calculate an error value.

That is, in the stack rotating step (S30), after the rotation of theprimary stack 10 a and the secondary stack 10 b, it is measured whethera position change occurs.

The primary and secondary reference lines refer to lines by which theprimary stack 10 a disposed on the table 110 is equally divided to besymmetrical to each other in a width direction or a longitudinaldirection.

Electrode Assembly Manufacturing Step

As illustrated in FIG. 9, in the electrode assembly manufacturing step(S40), a tertiary stack 10 c is manufactured on the top surface of theprimary stack 10 a to complete an electrode assembly 10.

That is, in the electrode assembly manufacturing step (S40), the firstelectrode 11 and the second electrode 12 are alternately stacked withthe separator 13 therebetween on the primary stack 10 a disposed on thetable 110 to manufacture the tertiary stack 10 c. Here, the secondelectrode 12 is stacked at the lowermost end of the tertiary stack 10 c.

Thus, in the electrode assembly manufacturing step (S40), the electrodeassembly 10 in which the tertiary stack 10 c, the primary stack 10 a,and the secondary stack 10 b are sequentially stacked may be completed.

Here, in the electrode assembly manufacturing step (S40), the separator,the first electrode, and the second electrode may move by the errorvalue measured in the stack rotating step (S30) and then be stacked onthe primary stack 10 a to prevent stacking failure from occurring.

For example, in the electrode assembly manufacturing step (S40), atertiary stack 10 b having a ten-layered structure in which the secondelectrode 12, the separator 13, the first electrode 11, the separator13, the second electrode 12, the separator 13, the first electrode 11,the separator 13, the second electrode 12, and the separator 13 aresequentially stacked on the top surface of the primary stack 10 adisposed on the table 110 in the vertical direction is manufactured.Here, in the electrode assembly manufacturing step (S40), the secondelectrode 12 is stacked at the uppermost end, and accordingly, thetertiary stack has a stacked structure of which upper and lower portionsare symmetrical to each other with respect to the center.

Particularly, the secondary and tertiary stacks 10 b and 10 c have asymmetrically stacked structure with respect to the primary stack 10 a,and accordingly, a symmetrical electrode assembly may be easilymanufactured. Particularly, since the secondary and tertiary stacks havethe symmetrical structure, it is possible to prevent thefinished-product electrode assembly from being bent.

The electrode assembly manufacturing step (S40) further comprises aprocess of allowing the table 110 to descend so that the uppermost endof the stack stacked on the table 110 is constantly maintained inheight. Therefore, since there is no need to adjust the height of theloading member 120, the electrodes and the separators may be stablystacked.

Bonding Step

As illustrated in FIG. 10, in the bonding step (S50), the electrodeassembly 10 constituted by the primary, secondary, and tertiary stacks10 a, 10 b, and 10 c is bonded using the bonding member 150. Therefore,the finished-product electrode assembly 10 may be manufactured.

Accordingly, the scope of the present invention is defined by theappended claims more than the foregoing description and the exemplaryembodiments described therein. Various modifications made within themeaning of an equivalent of the claims of the invention and within theclaims are to be regarded to be in the scope of the present invention.

DESCRIPTION OF THE SYMBOLS

-   -   100: Apparatus for manufacturing electrode assembly    -   110: Table    -   120: Loading member    -   130: Gripper    -   140: Measuring member    -   150: Bonding member

1. A method for manufacturing an electrode assembly, the methodcomprising: a primary stack manufacturing step in which two firstelectrodes and a second electrode of the primary stack are alternatelystacked with separators therebetween on a top surface of a table so thatthe first electrodes are disposed at each of an uppermost end and alowermost end of the primary stack; a secondary stack manufacturing stepin which first electrodes and second electrodes of the secondary stackare alternately stacked with separators therebetween on top of theprimary stack at a first end of the primary stack so that one of thesecond electrodes is disposed at a lowermost end of the secondary stack;a stack rotating step in which the primary stack and the secondarystack, which are initially disposed on the table, are rotated togetherat an angle of 180° to change vertical positions of the primary stackand the secondary stack; and a tertiary stack manufacturing step inwhich first electrodes and second electrodes of the tertiary stack arealternately stacked with separators therebetween on top of the primarystack at a second end of the primary stack opposite from the first endso that one of the second electrodes is disposed at a lowermost end ofthe tertiary stack.
 2. The method of claim 1, wherein the stack rotatingstep comprises gripping the primary stack and the secondary stack, whichare initially disposed on the table, together by using a gripper,descending the table away from the primary stack, rotating the primarystack and the secondary stack together at an angle of 180° using thegripper, and ascending the table so that the secondary stack issupported on the table.
 3. The method of claim 2, wherein the stackrotating step further comprises photographing the lowermost end of theprimary stack disposed on the table by using a first photographing partand measuring a primary reference line of the primary stack from a firstphotographed image, photographing the uppermost end of the primary stackby using a second photographing part and measuring a secondary referenceline of the primary stack from a second photographed image, andcomparing positions of the primary reference line and the secondaryreference line with each other through a measuring part to calculate anerror value.
 4. The method of claim 3, wherein the reference line is aline by which the primary stack disposed on the table is equally dividedinto two parts that are symmetrical to each other in a width directionor a longitudinal direction.
 5. The method of claim 3, wherein, duringthe tertiary stack manufacturing step, the separators, the firstelectrodes, and the second electrodes of the tertiary stack move by adistance equaling the error value and are stacked on top of the primarystack.
 6. The method of claim 1, wherein the electrode assemblymanufactured by the tertiary stack manufacturing step has a stackedstructure of which upper and lower portions are symmetrical to eachother with respect to a center.
 7. The method of claim 1, wherein theprimary stack manufacturing step comprises descending the table so thatan uppermost end of a portion of the primary stack that has already beenstacked on the table is maintained at a constant height.
 8. The methodof claim 1, wherein the tertiary stack manufacturing step comprisesdescending the table so that the uppermost end of a portion of thetertiary stack that has already been stacked on the table is maintainedat a constant height.
 9. The method of claim 1, wherein, during thesecondary stack manufacturing step, the second electrode is stacked atthe first end of the primary stack.
 10. The method of claim 1, wherein,during the tertiary stack manufacturing step, the tertiary electrode isstacked at the second end of the primary stack.
 11. The method of claim1, further comprising, after the tertiary stack manufacturing step, abonding step of pressing the electrode assembly at a predeterminedpressure to bond the electrode assembly.
 12. An apparatus formanufacturing an electrode assembly, the apparatus comprising: a table;a loading member configured to alternately stack first electrodes andsecond electrodes with separators therebetween on a top surface of thetable to manufacture a stack; a gripper configured to grip the stackstacked on the table to rotate the stack at an angle of 180°; and ameasuring member comprising a first photographing part configured toprimarily photograph a lowermost end of the stack stacked on the table,a second photographing part configured to secondarily photograph anuppermost end of the stack after rotating the stack at the angle of180°, and a measuring part configured to calculate an error value bycomparing a primary reference line measured from a primarilyphotographed image of the stack with a secondary reference line measuredfrom a secondarily photographed image of the stack.
 13. The apparatus ofclaim 12, wherein the loading member is configured to stack theseparators, the first electrodes, and the second electrodes on a topsurface of a partially assembled portion of the stack while moving thepartially assembled portion of the stack by a distance equaling theerror value after rotating the partially assembled portion of the stackat the angle of 180°.
 14. The apparatus of claim 12, wherein, the tableis configured to descend away from the stack when the gripper grips thestack.
 15. The apparatus of claim 12, wherein each of the first andsecond photographing parts comprises an infrared camera.